Laminated glazing and means for its peripheral sealing

ABSTRACT

The invention concerns a laminated glazing comprising two substrates ( 1, 2 ) between which is provided an active system ( 3 ), the glazing is provided with first peripheral sealing means ( 5 ), in particular proof against water in vapour form, comprising at least a joint based on thermofusible polymer(s) selected among at least one of the following polymer families: vinylacetate-ethylene, polyisobutylene, polyamide, or based on a sealant, in particular derived from polyurethane, polysulphide or silicone. Said joint can also be associated with mechanical reinforcement and/or spacing calibration means between the two substrates.

[0001] The present invention relates to laminated glazing and moreparticularly to glazing which has functionalities imparted by one ormore layers and/or one or more discontinuous elements which may beorganic, mineral or hybrid organic/mineral in nature. Laminated glazingusually consists of two rigid substrates between which is based a sheetor a superposition of sheets of thermoplastic-type polymer. Theinvention also includes laminated glazing known as “asymmetric glazing”using a single rigid substrate of the glass type associated with severalsheets of polymer, including in general at least one based onpolyurethane. The invention also includes laminated glazing having atleast one interlayer based on a single-sided or double-sided adhesivepolymer of the elastomer type (that is to say one not requiring alaminating operation within the conventional meaning of theterm—laminating requiring heat and generally pressure to soften thethermoplastic interlayer and make it adhesive).

[0002] The abovementioned layers or discontinuous elements are generallyplaced against one of the rigid substrates (or against the single rigidsubstrate), between the said substrate and the polymer-based flexiblesheet or one of the said sheets. They may also be placed between twoflexible or semiflexible substrates which themselves are associated witha rigid substrate or may be placed between two rigid substrates. Theywill be denoted hereafter by the term “active systems”. The glazing maycomprise several active systems.

[0003] The first types of active system of interest to the invention arein general electrochemical systems, and more particularlyelectrocontrollable systems of the type in which the glazing hasvariable energy and/or optical properties. They also includephotovoltaic and electroluminescent systems.

[0004] These systems have very varied applications: photovoltaic cellsconvert solar energy into light energy.

[0005] Electrocontrollable systems make it possible to obtain, inparticular, glazing of which the darkening/degree of vision orfiltration of the thermal/solar radiation may be modified at will. Theseinclude, for example, viologen-based glazing which allows the lighttransmission or absorption to be regulated, as described in Patents U.S.Pat. No. 5,239,406 and EP-612 82.

[0006] Electroluminescent systems convert electrical energy directlyinto light, an example being described in Patent FR-2 770 222.

[0007] There is also electrochromic glazing which allows the light andthermal transmission to be modulated. This is described, for example, inthe Patents EP-253 713 and EP-670 346, the electrolyte being in the formof a polymer or a gel and the other layers being of mineral type.Another type is described in the Patents EP-867 752, EP-831 360,PCT/FR00/00675 and PCT/FR99/01653, the electrolyte this time being inthe form of an essentially mineral layer, all of the layers of thesystem then essentially being mineral: this type of electrochromicsystem is commonly referred to by the name “all-solid-state”electrochromic system. There are also electrochromic systems in whichall of the layers are of the polymer type, and then one speaks of“all-polymer” electrochromic systems.

[0008] In general, electrochromic systems comprise two layers ofelectrochromic material which are separated by an electrolyte layer andflanked by two electrically conducting layers.

[0009] There are also systems called “optical valves”: these arepolymer-based films in which are dispersed microdroplets containingparticles capable of lying in a preferred direction under the effect ofan electric field. An example of this is described in the Patent WO93/09460.

[0010] There are also liquid-crystal systems, which operate in a similarway to the previous ones: they use a polymer film placed between twoconducting layers and droplets of liquid crystals are dispersed in thesaid film, especially nematic liquid crystals having positive dielectricanisotropy. When a voltage is applied to the film, the liquid crystalsare oriented along a preferred axis, allowing vision. With no voltageapplied, the film becomes scattering. Examples of these are described inthe Patents EP-238 164, U.S. Pat. No. 4,435,047, U.S. Pat. No.4,806,922, U.S. Pat. No. 4,732,456. Mention may also be made ofcholesteric liquid-crystal polymers, such as those described in thePatent WO 92/19695.

[0011] A second type of active system of interest to the inventionrelates to layers or multilayers whose properties are modified withoutany electrical supply, due to the effect of heat or light: mention maybe made of thermochromic layers, especially those based on vanadiumoxide, thermotropic layers and photochromic layers. Within the contextof the present invention and throughout the present text, the term“layer” should be taken in its widest sense: the layers may just as wellbe made of mineral materials as organic-type materials, mostparticularly polymers, which may be in the form of polymer films or evenof gel films. This is especially the case with thermotropic gels, forexample those described in the Patents EP 639 450, U.S. Pat. No.5,615,040, WO 94/20294 and EP 878 296.

[0012] A third type of active system of interest to the inventionrelates to elements in the form of heating wires or grids, or conductinglayers heating by the Joule effect (these may be wires embedded in thesurface of the thermoplastic sheet, as described for example in thePatents EP-785 700, EP-553 025, EP-506 521 and EP-496 669).

[0013] A fourth type of active system of interest to the inventionrelates to layers or multilayers having solar-control or low-emissivityproperties, especially those based on one or more silver layersinterspersed by dielectric layers. These multilayers may be deposited onone of the rigid substrates or on a flexible substrate of the PET(polyethylene terephthalate) type which is placed between two sheets ofthermoplastic polymer of the PVB (polyvinyl butyral) type joiningtogether the two rigid substrates of the glass type. Examples of theseare found in the Patents EP-638 528, EP-718 250, EP-724 955, EP-758 583and EP-847 965.

[0014] Some of these systems require means of electrical connection toan external current source, which must be designed so as to avoid anyshort circuit. All these systems have in common the fact that they may,to a greater or lesser extent, be sensitive to mechanical or chemicalattack, to contact with water or to exchanges with the outside.

[0015] These are the reasons why, in order to preserve their correctoperation, these active systems are usually placed against at least oneprotective carrier substrate. They are usually placed between twoprotective substrates, for example made of glass, or made of a rigid,semirigid or flexible polymer, either by direct contact or via one ormore thermoplastic-type joining polymer sheets. They usually have thelaminated structure described above. Peripheral sealing means are oftenprovided, the purpose of which is to isolate the active system as far aspossible from the outside. It is general practice to use butyl rubberseals combined with silicone or polysulphide seals, which are capable,in particular, of limiting the diffusion of water from the active systemto the outside, and vice versa.

[0016] However, these seals are capable of improvement on several countssince they must meet as best as possible at least three requirementswhich are not necessarily compatible. Firstly, as we have seen, theymust isolate the active system from the outside. They must therefore actas efficiently as possible as a barrier, especially to water in vapourform. The seals used hitherto are not entirely satisfactory from thisstandpoint. Secondly, their fitting—the way in which they are placedalong the edge of the devices—is not necessarily the simplest from theindustrial point of view. Finally, their mechanical properties can bewell below what is required.

[0017] The object of the invention is therefore to improve the design ofthe peripheral seals for sealing the aforementioned laminated glazing,especially with regard to their chemical properties and/or theirmechanical properties and/or their fitting and/or their configurationwith respect to the substrates protecting the active systems.

[0018] The subject of the invention is firstly laminated glazing, thevarious structures of which have been described above and which includesan “active system” from among one of those mentioned previously, whichis placed between two substrates of the said glazing. The inventionconsists in providing this glazing with a first peripheral sealing meansfor the active system, especially one sealing against water in vapourform, comprising at least one seal based on one or more hot-meltpolymers chosen from at least one of the following polymer families:ethylene-vinyl acetate, polyisobutylene and polyamide. These polymersare also in the form of copolymers and branched polymers. These threefamilies of hot-melt polymers are particularly advantageous for at leasttwo reasons: they provide high intrinsic sealing and are, in particular,highly impermeable to water in vapour form. As they are hot-melts, theyare also particularly easy to process, at a lower cost: they may beeasily injected in liquid or semiliquid form at the desired points byknown industrial means. They may also be fitted in the form ofpre-extruded or precast beads.

[0019] These polymers preferably constitute between 40 and 98% by weightof the constituent material of the seal. Additives may be added to them,these especially having three different functions:

[0020]

firstly, at least one crosslinking agent, for example of the isocyanateand/or epoxide type, may be added;

[0021]

secondly, a number of mineral fillers, preferably in powder form, may beadded, and for example aluminium or magnesium oxide, silica sand,quartz, diatomaceous earth, thermal silica, also called pyrogenicsilica, and nonpyrogenic silica. The fillers may also be silicates suchas talc, mica, kaolin, glass microspheres, or other mineral powders suchas calcium carbonate, or mineral fibres;

[0022]

finally, one or more resins called “tackifying resins” or “tackifiers”may be added, the function of which is to improve the adhesion of theseal to the material with which it will come into contact. When it isinserted between two substrates, the tackifier will therefore be acompound for improving the mutual adhesion between the seal and thesubstrate (glass, polymer, etc.) or between the seal and the materialcapable of covering the substrate in their contact regions (minerallayer, etc.). They may especially be compounds of very low molar mass,of at most 10,000, especially less than 5000 or between 500 and 2000,and a softening point preferably between 50 and 130° C., especiallybetween 90 and 100° C. An example is a saturated hydrocarbon aliphaticresin.

[0023] In point of fact it is important not only to choose a polymerwhich is intrinsically impermeable but which also adheres very well tothe materials with which it is in contact, so as to prevent the creationof diffusion paths at the interface between the seal and the material tobe sealed, so as to avoid any delamination of the seal. Instead of or inaddition to the use of such a tackifier, it is also possible to vary thedistribution of the molar masses present in the hot-melt polymer, mostparticularly in the case of polyisobutylenes: mixing several molarmasses results in good creep resistance at high temperature (in the caseof high molar masses) and also good adhesion, or good tack, to thematerials to be sealed (in the case of low molar masses).

[0024] In general, the seals according to the invention advantageouslyhave a softening point of between 70 and 180° C., especially between 90and 100° C. or between 145 and 170° C.; they may therefore be liquefiedin order to fit them or form them at industrially acceptabletemperatures.

[0025] Advantageously, they also have a viscosity of between 0.1 and 20Pa·s, especially between 0.8 and 8 Pa·s, measured at 190° C.

[0026] Finally, they advantageously have a water vapour permeability ofless than or equal to 5 or 4 or 3 g/m²/24 h, especially less than orequal to 1 g/m²/24 h, according to the ASTM E 9663 T standard; thismeans that they are particularly impermeable to water.

[0027] The hot-melt polymers of the seals described above may besubstituted with mastics, which are polymers behaving, when hot, likehot-melt polymers, but their transformation from the solid phase to theliquid phase, unlike in hot-melts, is not reversible (since they arethermosets). The advantage of being able to fit them into the glazing inthe liquid phase also applies in the case of this family of mastics,provided that those selected from them crosslink only after they havebeen fitted. Most particularly preferable are mastics based onpolyurethane, whose water vapour permeability is less than or equal to4, or even close to 2, g/m²/24 h. PU-based mastics meeting the desiredcriteria (especially having a water vapour permeability of less than orequal to 5 g/m²/24 h) are the mastics sold under the reference IS442 byTremco (permeability of 5 g/m²/24 h) and under the reference PU 3189/2by Le Joint Francais (permeability of 4 g/m²/24 h). The advantage ofthese particular mastics is that they ensure good impermeability both towater vapour and to liquid water, whereas it is preferable to “doubleup” seals based on hot-melt polymers with a second seal intended toserve as a barrier to liquid water (examples of these are mentionedbelow). They may also be polysulphide-based or silicone-based mastics.

[0028] To conclude on the chemical nature of the polymers used in theseals according to the invention, these hot-melt polymers are known tobe used in very different applications, for example in the shoe industryand in the production of cardboard articles, and have proved to beparticularly beneficial in the other totally different technical fieldrelating to the invention.

[0029] Another aspect of the invention relates to the way in which themechanical strength of the seals for such glazing can be improved,especially, but not exclusively, the hot-melt seals described above; thesubject of the invention is also the same type of glazing provided witha first peripheral sealing means, especially for sealing against waterin vapour form, which comprises at least one polymer-based seal andwhich is combined with means for mechanically reinforcing and/or forgauging the gap between the two substrates, between which the activesystem lies.

[0030] In a number of situations it is highly advantageous for the sealto have a significant mechanical strength. This is most particularly thecase when the device is in the form of laminated glazing comprising tworigid or semirigid substrates, between which the active system isplaced, and one or more joining polymer sheets. In this case, onesuitable configuration consists in ensuring that the joining polymersheet or sheets (together with the active system itself) has (have)smaller dimensions than those of the two substrates. Around theperiphery of the glazing is thus created a groove in which the seal orseals can be housed. However, this configuration may mechanically stressthe glazing too much during the lamination operation (which is usuallycarried out under pressure, and generally hot). This is because theedges of the glass-type substrates, in the region where theabovementioned peripheral groove lies, are cantilevered and, underpressure, tend to bend with respect to the more central part of the saidsubstrates.

[0031] The laminating operation will therefore tend to initiatedelamination at the edges of the thermoplastic sheets and consequentlyhave a tendency to generate bubbles. In the worst case, there may evenbe a risk of the glass substrates breaking. Under these conditions, itis extremely advantageous to use one or more peripheral seals which aremechanically reinforced; these mechanical reinforcements will be able tomaintain the appropriate gap between the two substrates around theirperiphery, by opposing their tendency to bend in the “critical”peripheral region of the groove, at least during the assembly operation.In certain applications, this mechanical reinforcement may also prove tobe very useful in the end product, independently of the fact that theremay or may not be a need for an assembly operation of the pressurelamination type.

[0032] A first type of reinforcing/gauging means may be in the form ofrigid or semirigid balls, especially made of metal of the aluminium orstainless steel type, or made of glass or made of ceramic. The balls mayalso be made of a zeolite, preferably a hydrophilic one.

[0033] It is known to use aluminium balls in the seals for curved doubleglazing, as described especially in Patents DE-91 162068, DE-41 04108and EP-499 525. However, in the case of double-glazing units, theirfunction is different: in a double-glazing unit, the “void” of materialbetween the two glass panes is not around the periphery, but in thecentral part of the glazing. Furthermore, double-glazing units do notundergo a hot pressure assembly operation. Finally, in the case ofdouble-glazing units, the balls used in the seals serve to maintain anominal gap between the glass panes of the final double-glazing unit,but counter the tendency of the edges of the glass panes to bend in theopposite direction to the bending that the laminated glazing of moreparticular interest to the invention tends to undergo.

[0034] The invention has therefore found a new application for theselocalized reinforcements known in the insulating glazing field.

[0035] A second type of reinforcing/gauging means may be in the form ofstuds. They may be of square, rectangular or trapezoidal cross section.They may be made of metal, glass, ceramic or low-melting-point glassfrit. Their geometrical shape can vary and may be any type ofpolyhedron. The important point is that they should preferably definebearing surfaces which are plane with respect to the substrate betweenwhich they will be placed. In fact, this type of stud is known in quiteanother application, namely in what are called “vacuum” double-glazingunits in which the vacuum is created between the two glass panes so asto achieve a very high thermal insulation for a minimum overall size.

[0036] Examples of these studs and of their methods of manufacture andof fitting are described in Patents EP-645 516 and EP-627 389.

[0037] These studs or these balls are preferably embedded in thepolymer-based seal, or at least partially incrusted therein. To combinethe balls with the seal, the device described in the abovementionedPatent DE-41 04108 may especially be used.

[0038] With regard to depositing the studs, these need to be depositedone by one in order for them to be placed correctly. Both in the case ofthe balls and in the case of the studs, a uniform spacing of theballs/studs along the seal may be provided. The spacing between twofollowing balls or two following studs may, for example, be from 1 to 5cm with, in any case, their systematic presence in the corners (one ballor stud on each side, close to the corner). The balls or studs may alsobe positioned so as to be spaced apart in a random fashion.

[0039] The third type of reinforcing/gauging means may be in the form ofa frame, especially made of metal, glass, ceramic or low-melting-pointglass frit. The cross section of the frame may be square, rectangular,etc., like that of the abovementioned studs. This frame may be made asone piece, or as several parts which are butted together during fitting.This may thus be compared with the structure of the generally metalframes/spacers which are used to maintain the gap between the glasspanes of standard double-glazing units. Advantageously, at least onepart of the bearing surfaces via which the frame bears on the substratesis coated with one or more polymer-based seals. It is thus possible tohave a frame of square or H-shaped cross section whose bearing surfacesare entirely coated with a seal before being fitted.

[0040] A fourth type of reinforcing/gauging means consists in using oneor more metal wires. Advantageously, these are entirelysheathed/embedded in a preformed polymer seal, for example a seal ofcylindrical cross section, which is then softened and fitted in anappropriate manner. These wires may be made of aluminium, steel orcopper, and preferably of a relatively ductile metal.

[0041] These various reinforcing means have to be sized appropriately.Thus, with regard to laminated glazing, it is preferable for thediameter (d₁) of the balls and/or the height (h₁) of the studs and/orthe diameter (d₂) of the metal wire or wires and/or the height (h₂) ofthe frame to be such that these various means can be housed without anyproblem between the two substrates. They may even serve to gauge theirspacing.

[0042] In laminated glazing, it is preferable for the followingrelationship to be satisfied:

½e≦h ₁ , h ₂ , d ₁ , d ₂ ≦e−0.1 mm,

[0043] where (e) is the total thickness of the thermoplastic interlayeror interlayers used for the lamination, or the desired gap between thetwo substrates, whether or not there is a polymer interlay. In general,this value (e) is between 0.025 mm and 1.25 mm, preferably between 0.35and 1.25 mm. (When there is a thermoplastic sheet, its thickness isgenerally between 0.35 and 1.25 mm; when there is a double-sidedadhesive polymer, its thickness is generally between 0.025 and 0.1 mm.The mechanical reinforcement is most useful in the case of thermoplasticpolymers.)

[0044] Advantageously, the glazing according to the invention includes asecond peripheral sealing means in the form of at least one seal whichseals against liquid water. This may especially be chosen to be based ona polyurethane, a silicone or a polysulphide.

[0045] This second peripheral sealing means may also take the form of aseal made of a thermoplastic polymer, for example polyvinyl butyral PVB,ethylene-vinyl acetate EVA, or certain polyurethanes. Advantageously,this seal may in fact be of the same chemical nature, or similarchemical nature, as that of the thermoplastic interlayers used tolaminate the glazing.

[0046] The interlayer or interlayers are thus cut so as to be set backwith respect to the two glass panes, in order to create a peripheralgroove in which to house the seal or seals, and measures may be taken toensure that the groove is provided with one or two seals as describedabove. Next, the “filling” of the groove may be completed with a stripof thermoplastic polymer of the same kind as the interlayers. Thesestrips correctly fulfil the role of sealing against liquids and are madeof a material already available since this has been used to make theinterlayers; this is a simple and effective solution, namely that ofthus “abducting” the thermoplastic sheets so that they fulfil the roleof complementary seals. This thermoplastic seal is preferably continuousall around the glazing. It may also be discontinuous. In this case it“imprisons” the other seal or seals placed before it in the peripheralgroove.

[0047] In this particular case, it is preferable for the first andsecond sealing means of the device to comprise seals which are adjoined.For example, two types of seals having chemically different formulationsmay be coinjection-moulded or coextruded. It is also possible to deposittwo pre-extruded or precast beads side by side. Measures may be taken toensure that all the seals are housed in the peripheral groove describedabove. This then results in a device whose sealing means are flush andnot “overhanging” the substrates, this being both aestheticallyattractive and practical when mounting the substrate in vehicles orbuildings.

[0048] It is possible to fit the seal or seals according to theinvention on the already assembled device. It is also possible to fitthem on one of the substrates of the device, before it is joined to theother substrate (with the abovementioned beads).

[0049] It is also possible to use a single seal provided that itschemical nature makes it satisfactorily impermeable both to liquid waterand to water vapour.

[0050] It is also possible to adapt the actual shape of the substratesof the device, in order to improve the effectiveness of the sealingand/or to make it easier to fit the seals. Thus, it is possible to usesubstrates whose inner edge (that turned towards the other substrate) isbevelled, thereby making it possible to define a wider peripheralgroove, which no longer has a simple rectangular cross section but whichhas an at least partly trapezoidal cross section, for example.

[0051] Advantageously, the seals used in the context of the inventionare placed so as not to come into contact with the electricallyconducting layers of the active system.

[0052] The invention will be described below in further detail with thefollowing nonlimiting examples using FIGS. 1a, 1 b, 2 and 3. Thesefigures show, in cross section, and highly schematically, laminatedelectrochromic glazing sealed according to the invention. The examplesall relate to “all solid-state” electrochromic glazing. Theelectroactive multilayer of an “all solid-state” electrochromic systemis typically as follows:

[0053]

a transparent first conducting layer made of fluorine-doped tin oxideF:SnO₂ (or tin-doped indium oxide ITO);

[0054]

a first layer of anodic electrochromic material, made of hydratediridium oxide (or hydrated nickel oxide);

[0055]

an electrolyte composed of a layer of tungsten oxide associated with alayer of hydrated tantalum oxide (or of aluminium-doped silicon oxideAl:SiO₂ or zirconium oxide ZrO₂ which may or may not be doped, forexample, doped with yttrium);

[0056]

a second, cathodic layer of electrochromic material, based on tungstenoxide, which is optionally hydrated; and

[0057]

a second transparent electrically conducting layer made of ITO forexample.

[0058] Further details about these layers or similar layers may be foundin the patents mentioned in the preamble to the application.

[0059] This multilayer is incorporated into the laminated glazing shownin FIGS. 1a, 1 b, 2 and 3: they are composed of two glass panes 1, 2having a thickness of 2.1 mm, between which are the electrochromicmultilayer 3 and a thermoplastic interlayer 4 made of polyurethane (PU)having a thickness of 0.76 mm (the PU may be replaced withethylene-vinyl acetate EVA).

[0060]FIGS. 1a, 1 b show the first seal 5 before assembly and then oncethe glazing has been assembled.

[0061]FIGS. 2 and 3 are variants, in which the inner edges of the glasspanes 1, 2 have been bevelled.

[0062] In all cases, the interlayer has dimensions which are smallerthan those of the two glass panes, so as to define a peripheral groovein which the seal is housed. When the glass panes are bevelled, theperipheral groove is no longer of rectangular cross section but oftrapezoidal cross section (FIG. 2) or of trapezoidal shape with roundededges (FIG. 3).

[0063] The seal 5 is then flush and entirely fills the groove. Anexample of the formulation for this seal is as follows:

[0064]

an ethylene-vinyl acetate base containing 5 to 40% vinyl acetate and 40to 95% ethylene (this is especially the EVA sold by National Starchunder the name “Instant Pak 2300” or the EVA sold by TRL under the name“Thermelt 2147/2157), this base possibly containing at least one of thefollowing additives:

[0065]

a tackifying resin;

[0066]

a crosslinking agent;

[0067]

a filler.

[0068] With this type of formulation, a seal is obtained which is bothremarkably impermeable to water in vapour form and adheres very stronglyto glass, making it very effective.

[0069] Alternatively, instead of the EVA-based seal, it is possible touse a seal based on a polyamide or polyisobutylene.

[0070] In the aforementioned example, the seal is a hot-melt. It cantherefore be melted and then injected under pressure into the peripheralgroove of the glazing once it has been assembled. It can also be fittedaround the periphery of the glass pane 1 before it is joined to theglass pane 2, the laminating operation gauging it to the desired crosssection under the effect of the pressure and possibly the heat.

[0071] A second seal (not shown) may usually be provided, thissurrounding the seal 5 and serving, in a known manner, to seal againstliquid water. It may be deposited as follows:

[0072]

by extrusion of polyurethane PU or of any thermoplastic elastomer TPE;

[0073]

by reactive injection moulding of PU;

[0074]

by thermoplastic injection moulding of a PVC (polyvinyl chloride)/TPEblend; and

[0075]

by injection moulding and vulcanization of an ethylene-propylene-dieneterpolymer EPDM.

[0076] A strip of PU or EVA of the same type as that of thethermoplastic interlayer 4 may also be provided.

[0077] The fitting may take place at the same time as or after the seal5 has been fitted (before or after assembling the glazing). It may be“overhanging”, covering the edges of the two glass panes, or adjoin theseal 5 in the peripheral groove of the glazing so that the combinationof the two seals is flush in the final laminated glazing.

[0078] The seal 5 is, according to a preferred variant, mechanicallyreinforced using glass or zeolite balls having a diameter of about 0.6mm (and therefore slightly less than the thickness of the PUinterlayer). These balls are partially inserted around the outer edge ofthe seal 5 using the device described in the aforementioned Patent DE-4104108.9, so that the spacing between two balls is about 2 cm. Theseballs play a very positive role in the assembly of the glazing. In FIGS.1a and 1 b it will be understood that, when the glazing is underpressure during the lamination operation, the edges of the glazingcorresponding to the peripheral region devoid of interlayer tend to bendin the direction indicated by the arrows. Consequently, there is a riskof the interlayer debonding at its periphery and even a risk of theglass breaking. The presence of the balls in the seal 5 will maintainthe spacing between the glass panes in this sensitive peripheral regionand prevent this bending phenomenon. These balls therefore act as localreinforcement during the lamination (of course, they continue toreinforce the seal in the final product). They are easy to fit,effective and inexpensive.

[0079] The invention has therefore developed a novel chemicalformulation for a seal and a novel means of mechanically reinforcing it.These sealing means are effective when it comes to protectinglayers/elements between two substrates which are sensitive to water and,in general, to any exposure to the atmosphere.

[0080] Of course, it is also possible to use them for glazing with anactive system operating in reflection (electrochromic mirror of therear-view mirror type, for example) or for glazing in which thethermoplastic interlayer is replaced by a film of double-sided adhesivepolymer.

[0081] The sealing means may also be applied to nonglass substrates.They may also be applied to active systems which require peripheralsealing but are not in the form of laminated glazing (double glazing,systems without a rigid substrate, etc.).

1. Laminated glazing comprising two substrates (1, 2) between which anactive system (3) is placed, characterized in that the said glazing isprovided with a first peripheral sealing means (5), especially onesealing against water in vapour form, comprising at least one seal basedon one or more hot-melt polymers chosen from at least one of thefollowing polymer families: ethylene-vinyl acetate, polyisobutylene andpolyamide, or based on a mastic, especially one based on polyurethane,polysulphide or silicone.
 2. Laminated glazing comprising two substrates(1, 2) between which an active system (3) is placed, characterized inthat the said glazing is provided with a first peripheral sealing means(5), especially one sealing against water in vapour form, comprising atleast one seal based on one or more polymers and combined with means formechanically reinforcing and/or for gauging the space between the twosubstrates.
 3. Glazing according to claim 2, characterized in that theseal (5) is based on one or more hot-melt polymers chosen from at leastone of the following polymer families: ethylene-vinyl acetate,polyisobutylene, polyamide or one based on a mastic, especially onebased on polyurethane, polysulphide or silicone.
 4. Glazing according toone of the preceding claims, characterized in that the active system (3)is an electrochemical system, especially an electrically controllablesystem having variable energy/optical properties, such as an allsolid-state electrochromic system, an optical valve system, aliquid-crystal system, a viologen-based system, a photovoltaic system oran electroluminescent system.
 5. Glazing according to one of thepreceding claims, characterized in that the active system (3) is athermochromic, thermotropic, photochromic, solar-control orlow-emissivity layer or multilayer.
 6. Glazing according to one of thepreceding claims, characterized in that the active system (3) is a gridof heating wires or a heating layer.
 7. Glazing according to one of thepreceding claims, characterized in that it is in the form of laminatedglazing with two rigid or semirigid substrates (1, 2) between which isthe electroactive system (3) surmounted by at least one interlayer (4)based on a thermoplastic polymer.
 8. Glazing according to claim 7,characterized in that the interlayer or interlayers (4) has (have)smaller dimensions than those of the two substrates (1, 2) so as tocreate a peripheral groove between the said substrates, the seal orseals of the first peripheral sealing means (5) being at least partly,and preferably entirely, housed in the said groove.
 9. Glazing accordingto claim 8, characterized in that the inner edge of at least one of thesubstrates, especially of both substrates, is bevelled so as to define awider peripheral groove.
 10. Glazing according to one of the precedingclaims, characterized in that the polymer-based seal or seals (5) of thefirst peripheral sealing means also includes (include) at least onecrosslinking agent, especially one made of an isocyanate and/or anepoxide.
 11. Glazing according to one of the preceding claims,characterized in that the polymer-based seal or seals of the firstperipheral sealing means also includes (include) a tackifying resin,especially one chosen from resins having a molar mass of less than10,000 or 5000, of the hydrocarbon aliphatic resin type.
 12. Glazingaccording to one of the preceding claims, characterized in that thepolymer-based seal or seals of the first peripheral sealing means alsoincludes (include) at least one mineral filler, especially one chosenfrom aluminium or magnesium oxide, silica sand, quartz, pyrogenic ornonpyrogenic silica, talc, mica, kaolin, glass microspheres and calciumcarbonate.
 13. Glazing according to one of the preceding claims,characterized in that the seal or seals of the first peripheral sealingmeans has (have) a softening point of between 70 and 180° C., especiallybetween 90 and 100° C. or between 145 and 170° C.
 14. Glazing accordingto one of the preceding claims, characterized in that the seal or sealsof the first peripheral sealing means has (have) a viscosity of between0.1 and 20 Pa·s, especially between 0.8 and 8 Pa·s, at 190° C. 15.Glazing according to one of the preceding claims, characterized in thatthe seal or seals of the first peripheral sealing means has (have) awater vapour permeability of less than or equal to 5 or 4 or 3 g/m²/24 haccording to the ASTM E 9663 T standard.
 16. Glazing according to one ofthe preceding claims, characterized in that the seal or seals of thefirst peripheral sealing means is (are) fitted by extrusion or injectionin the liquid phase.
 17. Glazing according to one of the precedingclaims, characterized in that the first peripheral sealing meanscomprises at least one polymer-based seal combined with means formechanically reinforcing and/or for gauging the gap between the twosubstrates, the said reinforcing and/or gauging means comprising rigidor semirigid balls, especially made of metal, of the aluminium or steeltype, or made of glass or made of ceramic or made of zeolite, preferablya hydrophilic zeolite.
 18. Glazing according to one of the precedingclaims, characterized in that the first peripheral sealing meanscomprises at least one polymer-based seal combined with means formechanically reinforcing and/or for gauging the gap between the twosubstrates, the said reinforcing and/or gauging means comprising studs,especially polyhedra having a square, rectangular or trapezoidal crosssection, for example made of metal, glass, ceramic or low-melting-pointglass frit.
 19. Glazing according to one of the preceding claims,characterized in that the first peripheral sealing means comprises atleast one polymer-based seal combined with means for mechanicallyreinforcing and/or gauging the gap between the two glass panes, the saidreinforcing and/or gauging means comprising one or more metal wires. 20.Glazing according to one of claims 17 to 19, characterized in that theballs and/or studs and/or metal wires are embedded in the polymer-basedseal, or at least partially incrusted in the said seal.
 21. Glazingaccording to one of the preceding claims, characterized in that thefirst peripheral sealing means comprises at least one polymer-based sealcombined with means for mechanically reinforcing and/or for gauging thegap between the two substrates, the said reinforcing and/or gaugingmeans comprising a frame, especially made of metal, glass, ceramic orlow-melting-point glass frit.
 22. Glazing according to claim 21,characterized in that at least one part of the bearing surfaces viawhich the frame bears on the substrates is coated with one or morepolymer-based seals.
 23. Glazing according to one of claims 17 to 22,characterized in that it is in the form of laminated glazing with thetwo rigid or semirigid substrates (1, 2) between which the active system(3) and optionally one or more interlayers (4) based on a thermoplasticpolymer are placed and in that the diameter (d₁) of the balls and/or theheight (h₁) of the studs and/or the diameter (d₂) of the wire or wiresand/or the height (h₂) of the frame is between ½e and e−0.1 mm where (e)is the total thickness of the interlayer or interlayers (4), or thedesired gap between the two substrates (1, 2).
 24. Glazing according toclaim 23, characterized in that the value (e) is between 0.35 mm and1.25 mm.
 25. Glazing according to one of the preceding claims,characterized in that it includes a second peripheral sealing means, inthe form of at least one seal which seals against liquid water,especially one chosen which is based on a polyurethane, a silicone or apolysulphide.
 26. Glazing according to one of the preceding claims,characterized in that it includes a second peripheral sealing means inthe form of a seal made of a thermoplastic polymer of the PVB or EVAtype, especially one having the same nature as the polymer interlayer orinterlayers (4) used to laminate the said glazing.
 27. Glazing accordingto claim 25 or claim 26, characterized in that the first and the secondperipheral sealing means comprise seals which are adjoined.
 28. Glazingaccording to one of the preceding claims, characterized in that all theseals of the peripheral sealing means are housed in the peripheralgroove present between the two substrates (1, 2) because of the set-backof the thermoplastic polymer-based interlayer or interlayers (4),especially so as to obtain flush seals.
 29. Process for manufacturingthe glazing according to one of the preceding claims, characterized inthat the seal or seals of the peripheral sealing means are deposited byinjecting them in liquid form, by extrusion or in the form ofpre-extruded or precast beads, on the already assembled glazing or onone of the substrates of the glazing before assembly.